March 9, 2014
Accession Number: 22398332
Radiographic Image Enhancement/*instrumentation
Abstract: PURPOSE: To compare two angiography systems of different image capture technology, one with flat detector (FD) and one with image intensifier (II), in terms of entrance surface air kerma (ESAK) rate, detector dose (DD) rate and image quality (IQ), in interventional cardiology procedures concerning both adult and pediatric patients. MATERIALS AND METHODS: In order to determine ESAK and DD rates, a digital dosimeter and polymethylmethacrylate (PMMA) plates were used. For the evaluation of IQ, two contrast objects (the Leeds TOR 18FG and a 5 mm-thick Aluminum plate) were used and two figures of merit were defined in fluoroscopy and cine acquisition modes. Measurements of ESAK, DD rates and IQ were made for various fields of view, pulse and frame acquisition rates. RESULTS: For the particular setup used in this study was noted that ESAK values in the II system were generally larger than the respective values in the FD system (on average 70% for fluoro mode, 5 times for cine mode). When halving the fluoroscopy pulse rate, reduction in ESAK was not proportional, in fluoroscopy mode. Image quality evaluations indicated that II performs better in terms of low contrast sensitivity (LCS) and signal-to-noise ratio (SNR) than the FD system which performs better regarding high contrast resolution (HCR). However, when considering image quality in relation to ESAK the FD system performs better than the II system (with the exception of low thicknesses and zooms for high pulse rates in the fluoroscopy mode). CONCLUSIONS: The FD system, generally, provides a better image quality-dose relation than the II system although II unit provides better LCS and SNR. This means that with the right adjustments to both systems, FD unit is able to provide same image quality with lower dose. However, newer technology does not automatically imply better image quality and further investigation is necessary for deriving safe conclusions for units which utilize different capture technology.